bcachefs: Update iter->real_pos lazily

peek() has to update iter->real_pos - there's no need for
bch2_btree_iter_set_pos() to update it as well.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -1470,14 +1470,6 @@ static void btree_iter_set_search_pos(struct btree_iter *iter, struct bpos new_p
 	bch2_btree_iter_verify(iter);
 }
 
-void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
-{
-	bkey_init(&iter->k);
-	iter->k.p = iter->pos = new_pos;
-
-	btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
-}
-
 inline bool bch2_btree_iter_advance(struct btree_iter *iter)
 {
 	struct bpos pos = iter->k.p;
@@ -1994,6 +1986,7 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
 		__bch2_btree_iter_upgrade_nounlock(iter, 1);
 
 	bch2_btree_iter_set_pos(iter, pos);
+	btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
 
 	return iter;
 }

fs/bcachefs/btree_iter.h

@@ -177,7 +177,12 @@ struct bkey_s_c bch2_btree_iter_peek_cached(struct btree_iter *);
 
 bool bch2_btree_iter_advance(struct btree_iter *);
 bool bch2_btree_iter_rewind(struct btree_iter *);
-void bch2_btree_iter_set_pos(struct btree_iter *, struct bpos);
+
+static inline void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
+{
+	bkey_init(&iter->k);
+	iter->k.p = iter->pos = new_pos;
+}
 
 /* Sort order for locking btree iterators: */
 static inline int btree_iter_lock_cmp(const struct btree_iter *l,